As in most academic studies, the understanding
of the terminology used in the field is a major part of the learning process.
The words used in the field of microcomputers are unique, colorful, sometimes
descriptive, and sometimes obscure. They cannot be found in any commercially
available dictionary at the present time. The Institute of Electrical and
Electronics Engineers (IEEE), New York, has been engaged in a major project
begun by Dr. Martin Weik in 1979, of the creation of a comprehensive dictionary
of computer terminology. This writer has assisted the IEEE by serving on
the Computer Graphics subgroup which is part of eight major groups of scores
of users and scholars now helping to compile the meanings for approximately
5900 identified technical words used in relation to computers. The final
"draft" of the dictionary is scheduled to be available soon.

The following terms are commonly used
general computer words or are particularly applicable to microcomputer
graphics and should be learned by the student.

Abort: The voluntary ending
of a program or operation of a program in progress; most DOS-based programs
respond to ^C (hold down the <Ctrl> key and type the letter C), or ^X
or ^S or ^<Break> to abort the program or operation. Many Windows programs
use the <Esc> key to abort.

Address: The complete descriptive
location of a file on a hard or floppy disk, e.g., "C:\ACAD\DWG\XYZ.DWG"
is the address of an AutoCAD drawing file called "XYZ" which is located
within sub-directory "DWG" of directory "ACAD" on the "C:" disk drive.

Alphanumeric: Pertaining to
the characters (letters, numbers, punctuation marks, and signs) used by
a computer.

Application program: See "program"

ASCII: The acronym for American
Standard Code for Information Interchange, a widely used system for encoding
letters, numbers, punctuation marks, and signs as binary numbers which
can then be manipulated by a computer.

Aspect Ratio: The height to
width ratio of an image on an output device, which may be different from
the actual height to width of the object represented; varies with the type
of graphics card used and the design of the output device itself.

Attribute: Verbal information
associated with a graphic object.

Baud Rate: The number of bits
transmitted per second; also called "BPS"

Binary: Having two components
or possible states, e.g., either "on" or "off."

Binary Code: A system for representing
things by a combination of two symbols, such as one and zero, TRUE and
FALSE, or the presence or absence of voltage.

Binary number system: A number
system which uses two as its base and expresses numbers as a series of
zeros and ones.

Bit: The smallest unit of information
in a computer, equivalent to a single zero or one. The word "bit" is also
a contraction of "binary digit."

BOM: Bill of Materials. A list
of information generated by the computer program from data attached to
blocks of graphic data in a drawing file, by using "attributes". Examples
are door schedules, window schedules, room finish schedules, column schedules,
quantity survey, and cost estimates.

Boot up: Turn on the computer
in order to load the disk operating system (DOS) into memory; see also
"warm boot" and "cold boot".

Buffer: Computer memory reserved
for temporary storage of data.

Bug: A mistake in a computer
program.

Byte: A sequence of eight bits
treated as a unit for computation or storage. Each key on a computer keyboard
is represented by one byte of information.

CAD: Computer Aided Drafting.

CAAD: Computer Aided Architectural
Design

CADD: Computer Aided Drafting
and Design.

CAM: Computer Aided Manufacturing.

CIM: Computer Integrated Manufacturing

Central Processing Unit (CPU):
The part of a computer which interprets and executes instructions.

Character: A letter, number,
punctuation mark, or any other symbol which is generated on the monitor
screen by pressing a key on the keyboard.

Circuit board: The plastic board
on which electronics circuits are mounted.

Circular (or Polar) Array: Multiple
copies of an object which are drawn in a circular (or part of a circular)
pattern, with equal spacing between each.

Command: A specific word or
other entry, input to a computer software program, to provide an instruction
and initiate a function of the program.

Computer: A programmable machine
that accepts, processes, and displays data.

Computer Terminal: See "Terminal".

Compiler: A computer program
that translates another program written in high level language (i.e., more
understandable by a normal user) into machine code, so that the program
can run on the computer faster. For instance, AutoCad normally "compiles"
its menu and operating program language by means of a built-in compiler
which comes with AutoCad in order to speed up its operation.

Configuration: Providing a set-up
for a software program for use with specific peripheral devices, by installing
the proper software drivers into the program, by the user; configuration
need only be done once for each specific combination of hardware used.

Control keys: See "Function
keys."

Crash: The premature end of
a computer program due to a hardware fault, a bug, or error in the program.

Cross hair: Horizontal and vertical
crossed lines appearing on the monitor screen, which designate the current
working point of the drawing as located by the digitizer or mouse pointer.

CRT: Cathode Ray Tube, normally
called the "monitor".

Cursor: The movable blinking
dash or spot of light that indicates a point of action or attention on
the computer monitor screen, where the next alphanumeric character will
appear on the screen upon one's depressing a key on the keyboard.

Data: Information in the form
of bits and bytes which can be stored on disks, displayed in understandable
form on a monitor, and used by a computer.

Database: A computerized set
of files, containing comprehensive information on any subject; as applied
to a computer program type, any program which will allow listing of information
in a structured way, and allow sorting the information by name, date, length,
etc., and allow extracting information in similar groups; in AutoCad, the
list of all steps used to create a drawing file and the list of vectors
(endpoints and center points) of all lines, arcs, and circles which make
up the drawing.

Data extraction: The process
of producing a Bill of Materials report.

Data processing: Operations
carried out on data; mostly used in conjunction with computerized accounting
and bookkeeping.

Dedicated: Designed for one
specific operation.

Default: An assumption made
by a computer program when it is not given a specific instruction by a
user. For instance, in AutoCAD, the "default" linetype and color is continuous
and white, unless instructed otherwise.

Digital: Pertaining to the representation
or transmission of data by discrete (i.e., on or off) signals

Digitize: To convert a hardcopy
of a drawing to a graphic computer form by using a digitizer tablet; to
represent data in digital, or discrete form.

Digitizer: A graphic input device
plugged into a computer which allows drawing of lines, arcs, and circles
in a drawing program, consisting of a "tablet" and a "pointer" (either
a stylus or a mouse).

Digitizer tablet: See "digitizer".

Disk: A round magnetized plate,
usually made of plastic or metal, organized into concentric tracks and
pie-shaped sectors for storing electronic data.

Disk drive: The electro-mechanical
mechanism which rotates a disk and reads or records electronic data from
or onto that disk.

Display: Another word for "monitor"
or "display monitor" or "video display terminal".

Dot matrix: A rectangular grid
of dots from which any alpha-numeric character may be constructed, usually
in reference to the type of print head which a printer has.

Driver: A computer program which
instructs a computer to reformat and recode data in such a way that it
can be used by a printer, a digitizer tablet, a plotter, or other peripheral
device, and which controls the communication to that device.

Electronics: The science or
use of electron-flow devices, such as vacuum tubes, and transistors, with
no moving parts.

Electrons: Particles of electrical
charge.

Entity: Basic graphic unit used
to create a drawing, such as a line, an arc, a circle, or a line of text.

Error message: A statement in
words displayed by a computer on the monitor when it has detected an erroneous
instruction or malfunction within its own system.

Extension: The last one to three
characters which follow a period in a file name, such as .DWG, or .PIC.

File: An organized collection
of electronic data, which is given a unique name of from one to eight alpha-numeric
characters so that it can be stored and retrieved from a disk in order
to be operated on.

Fillet: A curve of any radius
determined by the user which joins two non-parallel lines.

Floppy disk: A small (5-1/4"
in diameter) flexible disk coated with magnetic material used to store
electronic data; also called "floppy" or "floppy diskette."

Font: The design of a lettering
style.

Function keys: Special keys
on the keyboard, marked "F1" through "F10" which are defined by every software
program as having a special meaning and may effect several operations at
once by means of pressing only one key. For instance, the key "F1" in AutoCAD
"flips" the screen from a graphic mode to a text mode, whereas "F1" in
Wordstar can be defined by the user to mark the beginning of a block.

Gigabyte: A thousand million
bytes, or a thousand megabytes (ten to the ninth power).

Grid: A rectangular and regular
array of dots spaced at any distance determined by the user, used to reference
fixed locations on a drawing.

Hacker: Someone who loves to
experiment with computers.

Hard copy: A printout on paper
or a plot of a drawing on paper or mylar of computer data or a file.

Hatching: The filling of an
enclosed area of a drawing with a textured pattern; traditionally called
poche
in architecture.

Input: Information fed into
a computer by a user.

Input device: Any hardware device
used to enter data into a computer, e.g., keyboard, digitizer, mouse.

Input/Output (I/O) port: An
outlet on a computer circuit board for plugging in input or output hardware
devices such as printers, plotters, digitizers, keyboards, etc.

Joystick: A graphic input device
plugged into a computer which is a small box with a movable stick in it
which can be moved in all directions. The movement direction and magnitude
are sensed by the computer and a relative displacement of the cross hair
is made which allows drawing of lines, arcs, and circles in a drawing program.
Joysticks are not normally used in most professional graphics programs
due to their relative inaccuracy and somewhat artificial feel in relation
to manual drawing techniques.

Kilobyte (KB): 1,024 bytes (2
to the 10th power), used to express data storage quantities or computer
memory capacity, also called simply "KB" or "K".

Layer: A grouping of related
graphic entities, in a manner similar to an overlay drafting sheet, e.g.,
a layer of a plan drawing could contain all entities which represent walls,
another layer can contain all entities which represent doors, another windows,
another dimensions, another text, etc. Each layer can be made visible or
invisible at any time, thereby allowing them to be changed, plotted, copied,
etc.

Macro: A single command which
can be described in a program to initiate the performance of a group of
commands.

Mainframe computer: The largest
type of computer hardware, usually capable of serving many users simultaneously,
with a processing speed of about 100 times that of a typical micro-computer.

Megabyte (MB): A million bytes,
or a thousand kilobytes; also called simply "MB", "M", "a meg", and sometimes
"a ton".

Memory: The data storage facilities
of a computer, i.e. internal storage, as opposed to external storage
such as disks or tapes.

Menu: A list of options offered
by a program, displayed on the monitor for the user to choose from. A program
which makes use of this system is called "menu-driven," such as Wordstar
and AutoCAD.

Microcomputer: A desktop or
portable computer in which the CPU is contained on a single chip known
as a microprocessor. Microcomputers are meant for a single user, often
called a "home" or "personal" computer; IBM PC, PC-XT, and PC-AT are examples.

Minicomputer: A mid-sized computer
smaller than a mainframe, but larger than a microcomputer, and usually
with more memory than a microcomputer.

Mirroring: The process of creating
a mirror image of a drawing or a part of a drawing along a specified axis.

Modem: A device which can be
connected to a computer and to a telephone line that enables data to be
transferred between computers. The word is derived from the process which
is used to effect the transfer of data, that is, "MOdulator/DEModulator."

Mother board: A large circuit
board into which several smaller boards can be plugged; in the IBM PC microcomputer
family, the horizontally mounted board which is at the bottom of the computer.

Mouse: A small, handheld graphic
input device plugged into a computer which is moved around on a surface.
The movement direction and magnitude is sensed by the computer and a relative
displacement of the cross hair is made which allows drawing of lines, arcs,
and circles in a drawing program. Mice come in two general varieties, "roller
ball" mice, such as Microsoft Mouse, and "Optical" mice which work by reflection
of a low powered laser beam such as Mouse Systems Mouse.

Network: The linking together
of several computer systems.

Nybble: Half a byte, or four
bits; sometimes spelled "Nibble".

Operating system: A computer
program used to control, assist, or supervise all other programs which
run on a computer system; known as "DOS" to most users.

Output: The data returned by
a computer either directly to the user in the form of some kind of visual
appearance on the monitor, or to some kind of electronic storage device
such as a floppy disk.

Package: Another name for a
computer program, and including the instructions or documentation needed
to use it.

Pan: Moving of the point of
view of the user with relation to the drawing to show a different part
of the drawing on the monitor screen, analogous to moving a camera viewfinder
from right to left or up and down; panning does not change the apparent
size of a drawing, only the part displayed on the screen.

Parameter: Values input by a
program user to specify certain specific conditions.

Peripheral: A device, such as
a printer or digitizer tablet, or plotter, which is plugged into a microcomputer.

Pixel: The smallest area of
the monitor screen which can be independently highlighted and colored;
looks like a very small square dot on the screen; short for "picture element";
the more pixels which can be displayed across a monitor screen and from
top to bottom of the screen, the better the visual "resolution" of any
picture or data displayed on it.

Plotter: A robotic machine which
drives a pen to draw a computerized drawing file on paper, vellum, or mylar.

Pointer: A digitizer or mouse.

Port: An outlet on a computer
circuit board for plugging in hardware devices such as printers, plotters,
digitizers, keyboards, etc.

Primitive: See "entity".

Program: A series of detailed
instructions for performing some operation or solving some problem by computer.

Programmable: Capable of responding
to instructions and thus of performing a variety of tasks.

Prompt: A message or symbol
displayed by a software program on the monitor screen which informs the
user that the program is ready for input.

Mouse: A hand held device similar
in appearance to a mouse, with buttons and attached to a digitizer, used
to input points in a drawing.

RAM: An acronym for "Random
Access Memory" which is a form of temporary, internal electronic data storage
whose contents can be retrieved and altered by the user.

Raster: The electron beam that
draws a video picture by sweeping across the monitor screen and creating
a series of thin lines; also, a type of video graphics drawing which can
be described by means of pixel illumination only, as opposed to a geometrical
construction.

Read: The process by which the
CPU of a computer examines electronic data in memory or transfers data
to memory from an input medium such as a floppy disk.

Rectangular array: Multiple
copies of an object which are drawn in a rectangular pattern, arranged
in rows and columns, with equal spacing between each.

Repaint: Process of redrawing
a display image on the monitor screen to eliminate deleted entities or
to clean up the image.

Resolution: The fineness of
detail in a video display on the monitor, dependent on the size and number
of pixels on the screen. Resolution varies with the type of color graphics
card and type and size of monitor used in a microcomputer system.

ROM: An acronym for "Read Only
Memory" which is permanent factory-supplied internal memory containing
data or operating instructions that cannot be altered by the user.

Rubberbanding: In drawing a
line in a graphics computer program, the program automatically creates
a "stretchable" and movable line running from the first endpoint of the
line picked (indicated) by the program user, to the current cursor position,
determined by the location of the "pointer" (the digitizer puck, stylus,
or mouse); rubberbanding a line gives the user a visual image of how the
line would look at every new position of the pointer.

Run: The execution or carrying
out of a program by a computer.

Scrolling: Vertical movement
of text lines on the monitor screen.

Semiconductor: A solid crystalline
substance such as silicon whose electrical conductivity falls between that
of good conductors like metals and that of poor conductors like insulators
(such as rubber), and can be changed in nature of conductivity between
simulating these two types of materials.

Shell: Capability of accessing
a software program without exiting the program one is working in.

Silicon: The most abundant element
in the world from which transistors and computer chips are made.

Silicon Valley: An area of California
south of San Francisco that is the center of the semi-conductor production
industry in the United States.

Soft copy: Electronic data and
information displayed on a monitor screen, recorded on a disk, or on a
tape, or in any form that is not a hard copy, i.e., a printout on paper.

Software: Instructions or programs
in the form of electronic data stored on disks that enable a computer to
do useful work, as contrasted with "hardware" or the physical apparatus
of a computer system; also called a "program."

Source program: A program written
in a "source language" such as BASIC or Pascal, or LISP, that has to be
interpreted or "compiled" into machine code before a computer can run it.

Stylus: A hand held device similar
in appearance to a pen, attached to a digitizer tablet, and with a tip
which can be depressed against the tablet to "pick" points in the drawing,
and a button on the side of the barrel which has varying uses depending
on the program it is used with.

Tablet: The flat horizontal
portion of a digitizer, on which the puck or stylus are placed to pick
points in a drawing; see "digitizer".

Tablet overlay: A paper or plastic
sheet which is placed on top of the digitizer tablet, and containing a
menu of various programmatic functions which can be made to be input to
a program when picked by the user.

Terminal: A device composed
of a keyboard for putting data into a computer, along with a monitor and
printer for receiving data from a computer, normally located in a place
remote from the computer itself. This term is used mostly in conjunction
with mainframe or minicomputers.

Thumbwheels: A horizontally
aligned and a vertically aligned wheels which are mounted to a computer
keyboard and connected to a computer. The movement direction and magnitude
of each wheel in relation to the other is sensed by the computer and a
relative displacement of the cross hair is made which allows drawing of
lines, arcs, and circles in a drawing program. Thumbwheels were the earliest
type of input device for mainframe and minicomputer graphics systems and
are not normally used at this time in the microcomputer systems due to
the difficulty and unnatural feel of the tool.

Transistor: A semiconductor
device used as a switch or amplifier of electronic signals.

Vacuum Tube: A closed glass
tube with conductors inside it and pins at one end for connecting to electrical
circuit wiring, used as the earliest form of electronic switch, eventually
replaced by the transistor.

Window: A visual box displayed
on the monitor screen made by a computer program user to mark certain portion
of a drawing to look at it more closely, move it, erase it, copy it, etc.;
in another sense, the term "window" refers to a part of the monitor screen
which is used to display certain information; in the program "Symphony",
for instance, there may be several windows displayed at one time which
each show a piece of the total database or spreadsheet.

Word processor: A dedicated
computer, or a computer program which allows text to be entered and edited
on the monitor screen through the keyboard before it is printed on paper.
Such files which are created may be stored and re-used in the future for
other purposes.

Write: The process by which
a computer records data in memory, external storage or display devices.

Zoom: The enlarging or reducing
of a view of a monitor screen image, either to magnify a portion of the
drawing, or to see all of the drawing at one time; can be expressed as
"zoom in" to magnify, or "zoom out" to make drawing appear smaller; zooming
does not change the actual size of any entities, only the apparent size
on the screen.